Aircraft cowling systems for large jet engines typically include an inlet cowling, a fan cowling, a thrust reverser cowling, and a core cowling. These cowlings are usually hinged to move between a closed position and an open position. This allows access to the engine or the cowlings in order to perform inspections and maintenance.
Because adjacent cowlings are frequently constructed to have overlapping widths, there will be contact between the cowlings when they are opened and closed out of sequence. Overlap between adjacent cowlings also occurs because the cowlings pivot about axes that are not parallel, resulting in interference between the cowlings when they are moved to the closed position. This occurs most frequently between the thrust reverser cowling and the core cowling. As a result, it is imperative that these cowlings be closed in the proper sequence in order to prevent structural damage to the cowlings and the hinge mechanisms.
While there are a number of prior art devices that enable cowlings to be opened and closed, or to be locked in an open position, these devices do not ensure that adjacent overlapping cowlings are closed in the proper sequence to avoid contact. Proposed mechanisms for sequencing the movement of adjacent overlapping cowlings have been rejected due to complexity, cost, and installation difficulties. For instance, one system uses hydraulic interlock valves, hydraulic lines, hose assemblies and various mounting brackets and supports. This requires installation of hydraulic lines on the fan case and mounting of hydraulic valves in a location that maintains a normal environmental temperature of -30.degree. F. to +350.degree. F. This results in additional complexity, weight, and maintenance difficulties. This invention is directed to overcoming these disadvantages.